/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *    * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *    * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Functions for querying, manipulating and locking rollback indices
 * stored in the TPM NVRAM.
 */

#ifndef ANTIROLLBACK_H_
#define ANTIROLLBACK_H_

#include <types.h>
#include <security/tpm/tspi.h>
#include <vb2_sha.h>

struct vb2_context;
enum vb2_pcr_digest;

/* TPM NVRAM location indices. */
#define FIRMWARE_NV_INDEX               0x1007
#define KERNEL_NV_INDEX                 0x1008
/* 0x1009 used to be used as a backup space. Think of conflicts if you
 * want to use 0x1009 for something else. */
#define BACKUP_NV_INDEX                 0x1009
#define FWMP_NV_INDEX                   0x100a
#define REC_HASH_NV_INDEX               0x100b
#define REC_HASH_NV_SIZE                VB2_SHA256_DIGEST_SIZE

/* Structure definitions for TPM spaces */

/* Flags for firmware space */

/*
 * Last boot was developer mode.  TPM ownership is cleared when transitioning
 * to/from developer mode.
 */
#define FLAG_LAST_BOOT_DEVELOPER 0x01

/* All functions return TPM_SUCCESS (zero) if successful, non-zero if error */

uint32_t antirollback_read_space_firmware(struct vb2_context *ctx);

/**
 * Write may be called if the versions change.
 */
uint32_t antirollback_write_space_firmware(struct vb2_context *ctx);

/**
 * Read and write kernel space in TPM.
 */
uint32_t antirollback_read_space_kernel(struct vb2_context *ctx);
uint32_t antirollback_write_space_kernel(struct vb2_context *ctx);

/**
 * Lock must be called.
 */
uint32_t antirollback_lock_space_firmware(void);

/* Read recovery hash data from TPM. */
uint32_t antirollback_read_space_rec_hash(uint8_t *data, uint32_t size);
/* Write new hash data to recovery space in TPM. */
uint32_t antirollback_write_space_rec_hash(const uint8_t *data, uint32_t size);
/* Lock down recovery hash space in TPM. */
uint32_t antirollback_lock_space_rec_hash(void);

#endif  /* ANTIROLLBACK_H_ */